Wayne's World: Tiny jellyfish right at home in Fort Montgomery pond

Sunday

Sep 30, 2007 at 2:00 AM

They're mere blobs of ghostly ectoplasm. They pulse. They hardly seem to get anywhere. But they are everywhere in Maria Hannawalt's backyard pond in Fort Montgomery. These are freshwater — no bones — jellyfish.

They're mere blobs of ghostly ectoplasm. They pulse. They hardly seem to get anywhere. But they are everywhere in Maria Hannawalt's backyard pond in Fort Montgomery. These are freshwater — no bones — jellyfish.

In the ocean, you'd expect to find jellyfish. But jellyfish sucking up microbits of microscopic critters in fresh water, deep in the woods, west of Route 9W, near West Point?

It's a tad unbelievable.

But Hannawalt knew she had jellyfish in her pond.

"We had been to the aquarium in Long Beach, Calif., and they had big ones so no question, these in my pond were exactly like them," Hannawalt said.

Whence they came is a mystery welcomed enthusiastically by Hannawalt's granddaughters, 7 and 14. They gleefully swim and navigate the pond in a small, blue-and-white paddle boat that keeps a leisurely pace. It's an ideal craft for jellyfish watching — a marvelous way to suspend time. Freshwater jellyfish are underwater ballet dancers — contracting muscles to force water out of their squishy bodies. Sort of slo-mo jet propulsion.

HOLD ONE UP TO THE LIGHT in Hannawalt's jar. Basically, these jellyfish wear what scientists call a "double-skinned umbrella" filled with jelly, with some dark stuff in the middle.

Just as the kids move the paddle boat by pushing on its foot pedals, jellyfish can "flex" their muscles more on one side of their bodies than the other to get around rocks and things. They can't see. Scientists say they manage by using pigment cells sensitive to light.

Scooping up adult jellyfish the size of quarters and marveling at them in jars is a pastime that Hannawalt, who's seen plenty to wonder about in 30 years as a school bus driver, enjoys as much as her granddaughters.

"The jellyfish are like polka dots in the water, there are so many of them,'' Hannawalt exclaimed after a good jar dip captured a flotilla of what look like very small, fringed (maybe 99.26 percent water) Baggies.

Indeed, down in the greenish-tinged, spring-fed depths of the 12- to-14-foot-deep pond her husband dug are tentacle fringed jellyfish on the hunt. They rise from the depths and then float down, with stinging tentacles extended to catch whatever comes their way. And yes, they sting, some people have reported. If true, though, it's really small voltage.

SO HOW DID THESE CREATURES arrive at the Hannawalt pond that was dug in the 1980s? Could be in the mud on the feet of the ducks and herons that help make Hannawalt's backyard a jellyfish rendezvous — since last year? (Find where else they are in New York state by dialing up a serious jellyfish research center at Indiana University of Pennsylvania, which keeps a nifty freshwater jellyfish sightings locator, www.jellyfish.iup.edu/location.html. Hannawalt duly reported hers.)

Some say warm Augusts and Septembers can be a "bloom" time for freshwater jellyfish (known in Latin as Craspedacusta sowerbii).

The Western North Carolina Nature Center says freshwater jellyfish are found more often in artificial ponds than in natural bodies of water. If so, why? Maybe it's because critters that eat jellyfish (freshwater crayfish, for instance) aren't numerous enough to zap the jellies.

And how long they'll stay afloat in Hannawalt's pond is up to the jellyfish gods. Here's jellyfish population wisdom from the North Carolina nature people: The ectoplasmic jellyfish don't appear every year, even in ponds where their polyps thrive. But the polyps can shrink and sort of rest in winter so they might very well be back next year in the Hannawalt pond, which is one of the unsung backyard paradises around here. (Wayne's World is going to take a look at these backyards, from time to time.)

Hannawalt's got so much going on — great blue herons disappearing in the pond reeds, wood ducks showing off and even a red-tailed hawk seen flying with a snake in its talons — that she's transfixed sometimes — and "can't get a darn thing done."

Wayne A. Hall writes about the natural world for the Sunday Record. Reach him at scribewayne@aol.com.

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